Because of their relatively high fat and lipase content practically all oats for human consumption are traditionally submitted to a hydrothermal treatment which comprises dehulling, steaming and kilning.
Dehulling is generally carried out by an incomplete milling which provides dehulled oat groats and hulls. Steaming is generally carried out at a temperature from 90 to 100.degree. C. in order to increase the moisture content of the groats from an initial water content of about 9 to 13% to about 18 to 20%. Kilning is often carried from the top of a high column to the bottom over a period of about 30 to 90 minutes. The upper half the high column is held at about 95 to 105.degree. C. by dry indirect heating and vapour is drawn off from the lower part. The temperature of the groats in the lower part of the column is about 45 to 55.degree. C. and their moisture content is about 10 to 14%. Often the kilned groats are rehumidified and flaked, the flakes may be further ground to flour.
The stability of the comminuted, intermediate oat material thus obtained, namely of the kilned oat groats, oat flakes or oat flour is dependent on this traditional hydrothermal treatment. However, oat containing cereal products obtained by a process in which such a traditional intermediate product is subjected to further heat treatment is are less stable. Thus a method of producing an intermediate oat material which improves the stability of an oat containing cereal product obtained therefrom is needed.